Arctic Creek Facies, Arctic National Wildlife Refuge, Northeastern Alaska

John Decker, Wendy Camber, M. A. Vandergon, R. K. Crowder

The Arctic Creek facies consists of deformed Cretaceous (Albian) turbidites and shales that occur in poorly exposed low-relief hills at the eastern end of Ignek Valley in the Arctic National Wildlife Refuge (ANWR), northeastern Alaska. Preliminary studies of the Arctic Creek facies indicate that the section includes, from bottom to top, black shale (Jurassic to Early Cretaceous), manganiferous shale, interbedded dblack shale and siltstone turbidites, and sandstone turbidites (Albian). Bentonite occurs locally but its volume and stratigraphic significance could not be determined due to poor exposures. Beds are generally south dipping and the section has been repeated along north-vergent faults.

The Arctic Creek section is dissimilar to the typical Cretaceous section exposed elsewhere in Ignek Valley. The more typical Ignek Valley sequence consists of Kingak Shale (Jurassic to Neocomian), Kemik Sandstone (Hauterivian), Pebble Shale (Hauterivian-Barremian), Hue Shale (Aptian? to Santonian), and turbidites of the Canning Formation (Campanian to Paleocene). The two main differences that distinguish the Arctic Creek section from the typical Ignek Valley section are: (1) lack of the regionally persistent Kemik Sandstone in the Arctic Creek section, and (2) lack of Albian turbidites in the typical Ignek Valley section.

The Arctic Creek section is more similar to the Cretaceous section exposed at Bathtub Ridge about 180 km to the southeast. The Bathtub Ridge section consists of black shale with local siltstone beds (Jurassic to Lower Cretaceous), manganiferous shale, interbedded shale and siltstone turbidites (Albian), and sandstone turbidites (Albian?).

We believe that the Arctic Creek and Bathtub Ridge sections were once part of a continuous depositional basin, and that the Arctic Creek section has been thrust northward into juxtaposition with the typical Ignek Valley strata.

AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.